Display the two labels side by side as pupils settle. Take three hands-up answers, not open call-outs, and don't confirm yet — the surprise that they weigh exactly the same is the hook for the whole lesson. Write 1 kg = 1,000 g on the board to hold the question open.

Point at the gap chip carrying the × 1,000 throughout.

Worked example on the board first (narrate, do not rely on the interactive to animate the split): 1,500 g → kg and g.

• Bigger unit → ÷ 1,000.
• 1,500 ÷ 1,000 = 1 full kg, remainder 500 g.
• Write 1 kg 500 g. Leftover does not become another kilogram.

Slip to watch: pupils writing 1.5 kg or dropping the 500 g. Keep kg and g, never a decimal kilogram.

Ex 1, 1 kg to g: same weight, two names. 1 kg = 1,000 g. Link back to the sugar and flour from the hook.

Ex 2, 2 kg to g: pause before the reveal, take a prediction. If 1 kg is 1,000 g, how many grams in 2 kg? Answer 2,000 g, each kilogram carries another thousand.

Ex 3, 1,500 g to kg and g: replay the board example on the ladder so the digits step into place. Result 1 kg 500 g.

Ex 4, 1 kg 200 g to grams: combine first, the kilogram is 1,000 g, still have 200 g, together 1,200 g. Ladder can show 1,200 g and 1 kg 200 g as the same weight.

Don't move on until the class can say × 1,000 goes to grams, ÷ 1,000 goes back, and a mixed unit is combined first before reading the total in grams.

This round is for talking it through together — pupils take turns at the board and the class agrees or corrects out loud.

Rotate two pupils, one per weight. Before each drag, ask the class: are we going to a smaller unit or a bigger one?, that decides multiply or divide.

• 3 kg → g, a clean × 1,000; 3,000 g.
• 4,000 g → kg, a clean ÷ 1,000; 4 kg with nothing left over.

These are the practice questions — pupils take turns at the board, check each answer, and the class confirms before moving on. Keep the board work brisk rather than over-explaining.

The last two are the ones that catch people out. For 1,300 g, pupils divide by 1,000 to get 1 kg with 300 g left over; watch that the leftover is not dropped or turned into another kilogram. For 2,250 g the split is 2 kg 250 g. Ask each pupil to predict before they press Check.